Sheet processing machine

ABSTRACT

A sheet processing machine receives sheets from a sheet feeder. The sheets are inspected and their trailing ends are trimmed. Subsequently, the sheets are turned and are split into a plurality of partial sheets or sheet pieces. The now trailing ends of the sheet pieces are trimmed. The sheet pieces are separated axially and are delivered to a sheet receiving device where the individual sheet pieces are deposited in various stacks.

FIELD OF THE INVENTION

The present invention relates to a method for cutting sheets and to a sheet processing machine. A trailing end of a sheet is cut perpendicularly to a sheet transport direction by a first transverse cutting device. This sheet is then rotated or turned and the now trailing end is cut by a second transverse cutting device.

DESCRIPTION OF THE PRIOR ART

DE-AS 10 44 589 describes a transverse cutting device for paper webs. A belt system for transporting the sheets cut from the web is connected downstream of the transverse cutting device.

DE 43 13 452 A1 describes a device for cutting sheets from a web. Two transverse cutting mechanisms are provided with this device, by means of which first a leading end of the web is exactly cut to measure and the sheet is then cut off the web.

DE 42 38 387 A1 discloses a cut registration regulating device on transverse cutters of rotary printing presses. Here, a rotating cylinder is provided, which works together with a stationary opposed cutter.

SUMMARY OF THE INVENTION

The present object of the invention is based on creating a method for cutting sheets, and on a sheet processing machine with a cutting device.

In accordance with the invention, this object is attained providing a sheet processing machine which initially trims a trailing end of a sheet perpendicularly to a sheet transport direction by use of a first transverse cutting device. The sheet is then turned so that the trimmed trailing end now leads. The now trailing end of the sheet is trimmed perpendicularly to the sheet transport direction by a second transverse cutting device.

Present invention lie, in particular, in that transverse cutting from the start to the end of a sheet takes place without manual intervention in a sheet processing machine. It is possible by means of integrated inspection devices, to control the print quality itself, as well as the cut registrations in the sheet processing machine. In this way, it is possible to simultaneously control the fronts and backs of the sheet, which were printed, for example, on the obverse and reverse sides of the sheet.

A simple cut registration adjustment is possible because of the working together of the transverse cutting devices with a chain conveyor. This adjustment is advantageously performed by means of a position-controlled electric motor driving a cutting cylinder.

A longitudinal cutting device is assigned to a processing cylinder of the sheet processing machine, so that the sheet is cut “in-line” into two or more partial sheets. These sheets can be deposited on stacks, which can be selected by means of the inspection device. In this manner, sorted stacks with “good” and with waste sheets are formed. This has the advantage that, in case of a defective partial sheet, the entire sheet is not wasted.

By means of this sheet processing machine all sides of a sheet are cut and the latter is cut into partial sheets. All cuts made, as well as the obverse and reverse printing, are controlled by means of inspection devices, all of the cut sheets are deposited on selectable stacks.

This sheet processing machine performs a plurality of processing steps “in-line”, which leads to an increase in production and also to a reduction of manual labor. Moreover, the quality of the products made in this way is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The sheet processing machine in accordance with the present invention is represented in the drawings and will be described in greater detail in what follows.

Shown are in:

FIG. 1, a schematic lateral view of a sheet processing machine;

FIG. 2, a schematic representation of the processing steps in the sheet processing machine;

FIG. 3, a schematic view from above on a stack of a delivery device of the sheet processing machine;

FIG. 4, an enlarged schematic lateral view of a processing cylinder of the sheet processing machine in accordance with FIG. 1; and

FIG. 5, an enlarged schematic view from above on the processing cylinder of the sheet processing machine in accordance with FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A sheet processing machine 1 for the transverse and longitudinal cutting of sheets 2 in accordance with the present invention is shown in FIG. 1, and has integrated inspection devices 3, 4, 6. The sheets preferably are printed paper sheets, for example securities. For instance, this sheet processing machine 1 is constructed as will be described in what follows:

A feeder 7 essentially has a first stack 8, a sheet separating device 9 and a delivery table 11. This feeder 7 is followed by an installation 12 which is designed as a swing feeder. A first chain conveyor 13 works together with this swing installation 12. This chain conveyor 13 has a pair of revolving chains 14, to which axially extending chain gripper systems 16 have been attached. The chains 14 are reversed by a first, chain wheel carried on a first chain wheel shaft 17, and by a second chain wheel carried on a second chain while shaft 18. The chains 18 extend at least partially along a straight line between the first, 17, and second chain wheel shaft 18. Viewed in the transport direction T, the first inspection device 3 is arranged downstream of or often the first chain wheel shaft 17. This first inspection device 3 has a suction box 19, whose work surface facing the chain gripper system 16 is made at least partially transparent. Illumination installations, not specifically represented, are arranged under this transparent work surface.

A first transverse cutting device 21 is connected downstream of this suction box 19 of the first inspection device 3. The first transverse cutting device 21 has a rotating cutting cylinder 22 and a stationary opposed cutter 24 fastened on a cross bar 23. The cutting cylinder 22 is provided with at least one axially extending groove, into which a passing chain gripper system 16 can descend. A width of the groove in the circumferential direction of the cutting cylinder 22 is made larger than a width is required to receive the chain conveyor 16. The cooperation chain gripper systems 16 the cutting cylinder 22 can be phase-shifted in respect to each other for adjusting the cut registration. In the sheet processing machine in accordance with the present example, rotating arms are provided on both sides of the cutting cylinder 22, between which an axially extending cross bar is arranged to receive a cutter 26.

The cutting cylinder 22 has a drive, whose phase can be changed in respect to the chain conveyor 13. In the present invention this drive, is advantageously embodied as a separate, position-controlled electric motor.

The stationary opposed cutter 24 is arranged in a slightly oblique direction in respect to the axis of rotation of the cutting cylinder 22, i.e. the opposed cutter forms an opening angle, with the transport direction T, which is not equal to 90° but is, for example 89°. From this, an angle of inclination of the opposed cutter 24 of, for example, 1° in respect to the axis of rotation of the cutting cylinder 22 results. The opposed cutter 24 is also slightly rotated around its longitudinal axis, i.e. the opposed cutter 24 has a slight twist. This insures that the first transverse cutting device 221 will make a cut in the moving sheet which is perpendicular to the longitudinal direction of the sheet.

The electric drive mechanism of the cutting cylinder 22 follows the speed of the chain conveyor 13 at an identical circumferential speed. Because of the twist of the cutter 24 and the superimposed conveying speed, an exactly right-angled cut of the sheet 2 is created in the end of the sheet 2 as the sheet 2 passes through the first transverse cutting device 21.

The axially extending cutter 26 which is carried by the cutting cylinder 22, is also slightly inclined or angled respect to the axis of rotation of the cutting cylinder 22 and also has a twist in longitudinal direction. The cutter 26 of the cutting cylinder 22 and the opposed cutter 24 are matched to each other.

A rotating opposed cylinder which, for example, has an opposed cutter 24 for performing a scissors cut, or an opposed strip, is also possible in place of the stationary opposed cutter 24. It is also possible to design the cutter 26 and the opposed cutter 24 parallel in relation to the axis of rotation of the cutting cylinder 22 and without a twist. The cutting cylinder 22, or respectively the opposed cylinder, can also have several cutters 26.

A second inspection device 4 is installed downstream of this first transverse cutting device 21 in the area of the chain conveyor 13. This second inspection device 4 essentially consists of a sensor 27, illumination devices 30 and a suction box 35.

A sheet turning device 28 follows the chain conveyor 13. In the present invention, this sheet turning device 28 essentially consists of a storage drum 29 and a turning drum 31. The storage drum 29 has a “double” circumference and is therefore equipped with two controllable gripper systems 32, which are arranged offset by 180° in respect to each other, and two oppositely located suction systems 33. A distance in the circumferential direction of the sheet storage drum between each of the gripper systems 32 and the suction systems 33 can be adjusted to the length of the sheets to be conveyed. The suction systems 33 are movable both in the circumferential direction and also in the axial direction of the sheet storage drum 29.

The turning drum 31 has two controllable gripper systems 34, 36, which are placed side-by-side and which are pivotably arranged around their longitudinal axis.

The turning drum 31 and the storage drum 29 can be phaseshifted in respect to each other.

A cylinder 37, for example a processing cylinder 37, and a cooperating longitudinal cutting device 38, are situated downstream of the turning device 28. This processing cylinder 37 has, for example, at least twice the circumference of the turning drum 51, and carries four holding systems 39, 41, 42, 43, which are designed as gripper systems 39, 41, 42, 43 and which are each controllable independently of each other. These holding systems 39, 41, 42, 43 can also be embodied as suction devices. Two of these gripper systems 39, 41, or respectively 42, 43 are respectively located in a cylinder groove approximately axis-symmetrical next to each other in the axial direction in relation to a center of the processing cylinder 37, and are displaceable in relation to each other in the axial direction. In the present invention, one of the gripper systems 39, or respectively 42, located axially next to each other, is arranged fixed in the axial direction, and the second gripper system 41, or respectively 43 of each pair of gripper systems 39, 41 or 42, 43, is displaceable in relation to the first gripper system 39, or respectively 42, for example by means of a cam 40 and cam rollers 45. However, both gripper systems 39, 41, or respectively 42, 43, can be displaceable. The second pair of these gripper systems 42, 43 is located opposite the first pair of two gripper systems 39, 41 designed in this way and is offset by 180°.

The longitudinal cutting device 38 which is also seen most clearly in FIG. 4 and which has a plurality of cutter wheels 44 and, which is assigned to the processing cylinder 37, is placed downstream, in the sheet transport direction T, shortly after the turning drum 31. In the present invention, the longitudinal cutting device 38 has an axially extending cross bar 46, on which three cutter wheels are arranged each of, which can be independently actuated and axially displaced.

A second chain conveyor 47 with two rotating chains 48 is arranged after the processing cylinder 37. A plurality of chain gripper systems 49 are arranged on these chains 48. These chain gripper systems 49 each consist of two chain gripper assemblies, which are placed next to each other in the axial direction, are approximately symmetrically arranged in relation to the machine center and can be operated independently of each other. In place of the processing cylinder 37, the second chain conveyor 47 can also have chain gripper systems which can be moved in relation to each other in the axial direction.

It is also possible that more than two gripper systems 39, 41, or respectively 42, 43, i.e. any arbitrary number, are displaceable on the processing cylinder 37. In case of three gripper system set in, which the gripper systems are arranged axially next to each other, the gripper system arranged in the center of each of the three, for example, could be fixed in place in the axial direction, and the two outer gripper systems could be designed so that they can be shifted away from the center system.

The chains 48 are reversed by a first chain wheel shaft 51 and second chain wheel shaft 52. A median line, constituted by the chain wheel shaft 51 and the processing cylinder 37, forms an opening angle B of less than 180°, for example 155°, with a median line constituted by the processing cylinder 36 and the longitudinal cutter wheels 44.

Downstream of the first chain wheel shaft 51 of the second chain conveyor 47, a suction box 56 is arranged in the second chain conveyor 47 underneath the chain 48. A second transverse cutting device 57 follows this suction box 56, which is constructed in a manner identical with the first transverse cutting device 21. The first and second transverse cutting devices 21, 57 respectively are used for trimming the ends 71, 72 of the sheets 2, 82, 83. The third inspection device 6 with a sensor 58, illumination devices 59 and a suction box 61, is connected downstream of this second transverse cutting device 57.

A cut sheet feeder 62 in the area of the chain conveyor 47 follows the third inspection device 6. This cut sheet feeder 62 has six stacks 63, 64, 66 to 69, respectively two of which are arranged in pairs next to each other, as shown in FIG. 3. The resulting three pairs of stacks 63, 64, or respectively 66, 67, or respectively 68, 69, are arranged behind each other. The stacks 63, 64, or respectively 66, 67, of the first two pairs of stacks respectively have common lifting devices, so that respectively one pair of stacks can be raised and lowered together. Separate lifting devices have been provided for the two stacks, 68, 69 located next to each other, so that the two stacks, 68, 69 can be raised and lowered independently.

Gripper systems, or respectively chain gripper systems are understood to be a plurality of grippers, which are arranged on a shaft which can be pivoted around a longitudinal axis.

The functioning of the sheet processing machine 1 in accordance with the present invention is as follows:

A sheet 2, in particular a sheet of paper printed on the obverse and reverse sides, is fed from a first stack 8 to the delivery table 11 by the sheet separating device 9. The sheet 2 is grasped from this delivery table 11 by the swing feeder installation 12 and is passed over to a chain gripper system 16 in the area of the first chain wheel shaft 17 of the first chain conveyor 13. The chain gripper system 16 conveys the sheet 2 along the “straight” portion of the chain conveyor 13 to the first inspection device 3. The sheet 2 is checked, in segments, for damage such as, for example tears and holes, by means of the first inspection device 3. The water mark of the sheet 2 is also inspected by the use of back lighting. In the course of this conveyance the sheet 2 is guided by the suction box 19, to which a vacuum has been applied, of the first inspection device 3.

The chain gripper system 16 conveys the sheet 2 through the transverse cutting device 21 to the second inspection device 4. There, the sheet 2 is aspirated by the suction box 35 of the second inspection device 4 in the area of the front of the sheet 2. A trailing end 72 of the sheet 2 is still in the transverse cutting device 21, where a narrow strip 73, which extends in the axial direction, is cut off its end 73. In this case the conveying speed of the chain conveyor 13 and the circumferential speed of the cutter 26 are matched to each other, so that the trailing end 72 of the sheet 2 is trimmed at right angles in respect to the transport direction T all as depicted in FIG. 2.

This sheet 2 having a first cut 74 is now inspected in the second inspection device 4. In the inspection process, a front side or obverse side or of the sheet 2 and a fresh edge of the sheet 2 (cut registration resulting from the trimmed end 72 are inspected.

Thereafter, the chain gripper system 16 passes the front end 71 of this sheet 2 on to a gripper system of the storage drum 29. This storage drum 29 conveys the sheet 2 in the direction toward the turning drum 31. When front the end 72 of this sheet now reaches the area of the suction systems 33 of the storage drum, the latter aspirates the now trimmed trailing end 72. Subsequently the suction systems 33 of the storage drum 24 move in an approximate arrow shape away from the center of the storage drum 29 and in this way tense the sheet 2 in the circumferential direction as well as in the direction toward lateral edges of the sheet 2.

The phase shift between the turning drum 31 and the storage drum 29 is set to the length of the sheets 2 to be processed. The storage drum 29 conveys the front end 71 of the sheet 2 through the gap between the turning, 31 drum and storage drum 29 until the suction systems 33 reach this gap. The trimmed end 72 of the sheet 2 is grasped by the first gripper system 34 of the turning drum 31 and is released from the suction system 33 by turning off the vacuum. Thereafter both gripper systems 34, 36 of the turning drum 31 are pivoted against each other, and the trimmed end 72 of sheet 2 is passed from the first gripper system 34 to the second gripper system 36. In their continued course the gripper systems 34, 36 pivot back into their initial position.

The trimmed end 72 is now grasped by the gripper system 36 so that it leads, and the untrimmed front end 71 trails.

The sheet 2 is passed on by the turning drum 31 to a pair of gripper systems 39, 41, or respectively 42, 43 of the processing cylinder 37. On the processing cylinder 37, the sheet 2 is provided with three cuts 76, 77, 78 in the longitudinal direction—i.e. in the transport direction T—. Narrow strips 79, 81 are cut off the two longitudinal sides of the sheet 2 by the second and third cut 76, 77. These cuts 76, 77, 78 and strips 79, 81 can be seen in FIG. 2.

The gripper division or size of the gripper systems 39, 41, 42, 43 of the processing cylinder 37, and the width, as well as the position, of the sheet 2, are matched to each other in such a way that the two cut-off strips 79, 81 are not grasped by the grippers.

The fourth cut 78 separates the sheet 2 in the center into two partial sheets 82, 83. Here, too, there is no gripper in the area of the cut 78.

When these three longitudinal cuts 76, 77, 78 are completely performed, also at the maximum length of the sheet 2, the two partial sheets 82, 83 are moved apart in the axial direction. To this end, in the present invention a gripper system 41, or respectively 43, or 39, or respectively 42, performs a lifting motion in the axial direction by means of a cam roller 45 working together with a cam disk 40. Only after these two partial sheets 82, 83 have been moved away from each other are these two partial sheets 82, 83 passed on to a chain gripper system 49 of the second chain conveyor 47 in the area of the first chain wheel shaft 51. The gripper system 41, or respectively 43, of the processing cylinder 37 is moved back into its initial position before the next sheet 2 is taken over.

The spaced-apart partial sheets 82, 83 are conveyed on in a common conveying direction, or respectively plane.

The two partial sheets 82, 83 are conducted to the second transverse cutting device 57 by this chain gripper system 49. To steady the sheet 2, it is aspirated along the suction box 56 which is connected upstream of the second transverse cutting device 57, and the previously trimmed end 72 of the partial sheets 82, 83 in the chain gripper system 49 is already passed over the suction box 61 of the third inspection device 6. From the untrimmed initial front 71 of the sheet 2, i.e. of the two pulled-apart partial sheets 82, 83, which now trails, a strip 86 is axially cut off at right angles in respect to the transport direction T by means of a fifth cut 84. The sheet 2 has now been trimmed on all sides and has been separated into two partial sheets 82, 83.

A back or reverse side of the sheet 2, i.e. the backs of the two partial sheets 82, 83, together with the edges trimmed in the longitudinal direction, and the now trailing front 71 of the sheets 2, i.e. the trailing ends of the partial sheets 82, 83 trimmed in the axial direction, are checked by the third inspection device 6.

The inspection devices 4, 6 check the cut registration of the sheets 2, 82, 83, i.e. the position of at least one trimmed edge, preferably of all trimmed edges of the sheets 2, 82, 83 in relation to a reference marker, for example within a printed image. Preferably the entire sheets, including the entire printed image, are checked.

The chain conveyor 47 conveys the partial sheets 82, 83, which have been trimmed on all sides and checked on front and back from the third inspection device 6, to selected ones of the six stacks 63, 64, 66 to 69 of the feeder 62. There, the partial sheets 82, 83 can be selectively deposited on one of the six stacks 63, 64, 66 to 69. In this connection, the first four stacks 63, 64, 66, 67 preferably receive so-called “good” sheets, and the two last stacks 67, 68, which are arranged next to each other, receive waste sheets.

In place of sheets 2, 82, 83, it is also possible, for example, to trim or cut printed webs, i.e. printed materials, and to subsequently check them by means of one or several inspection devices 3, 4, 6. In this case, the cutting devices 1, 38, 57 can be arranged, for example, in the area of a folding mechanisms of a web-fed rotary printing press.

There, a web is cut, for example in the longitudinal direction, into several partial webs, and is subsequently cut into signatures in the transverse direction. In this case, the cut registration can be checked after each step, or after the web has been cut completely into signatures.

The inspection devices 3, 4, 6 preferably contain one or several CCD area cameras, which check the sheet as a whole.

While a preferred embodiment of a sheet processing machine in accordance with the present invention has been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that a number of changes in, for example, the type of printing press used with the sheet processing machine, the apparatus used to deliver and remove the sheet stacks and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only bey the following claims. 

What is claimed is:
 1. A method for cutting flexible sheets including: providing a flexible sheet processing machine having a direction of sheet transport; feeding flexible sheets to said flexible sheet processing machine; guiding said flexible sheets in said sheet transport direction in said flexible sheet processing machine; providing a first transverse sheet end cutting device in said flexible sheet processing machine; trimming a first trailing end of each said flexible sheet perpendicularly to said transport direction by using said first transverse sheet end cutting device. providing a flexible sheet turning device having a flexible sheet turning drum in said flexible sheet processing machine; locating said flexible sheet turning device after, in said sheet transport direction, said first transverse sheet end cutting device; directing each said flexible sheet having said trimmed first trailing end to said flexible sheet turning drum; turning each said flexible sheet in said flexible sheet turning device and placing said trimmed first trailing end of each said flexible sheet as a leading end; providing a second transverse sheet end cutting device in said flexible sheet processing machine after said sheet turning drum; directing each of said flexible sheets from said flexible sheet turning drum to said second transverse sheet end cutting device; and trimming a second trailing end of each said flexible sheet perpendicularly to said transport direction by using said second transverse sheet end cutting device.
 2. The method of claim 1 further including providing a longitudinal cutting device in said flexible sheet processing machine and using said longitudinal cutting device for cutting each of said sheets longitudinally into partial flexible sheets which lie next to each other.
 3. The method of claim 1 further including providing longitudinal edge trimming devices, and trimming edges of said flexible sheets extending parallel to said transport direction using said longitudinal edge trimming devices.
 4. The method of claim 1 further including providing longitudinal cutting and edge trimming devices in said flexible sheet processing machine, and locating said longitudinal cutting and edge trimming devices between said first and second transverse sheet end cutting devices.
 5. The method of claim 2 further including placing said longitudinal cutting device between said first and second transverse sheet end cutting devices and cutting each said flexible sheet into said partial sheets after turning each of said flexible sheets.
 6. The method of claim 1 further including placing an inspection device after said first transverse sheet end cutting device and checking each said flexible sheet cut by said first transverse sheet end cutting device.
 7. The method of claim 1 further including placing an inspection device after said second transverse sheet end cutting device and checking each said flexible sheet cut by said second transverse sheet end cutting device.
 8. The method of claim 2 further including placing an inspection device after a last one of said first and second transverse sheet end cutting devices and said longitudinal cutting device and inspecting said flexible sheets after all cuts have been made.
 9. The method of claim 1 further including placing an inspection device before said first transverse sheet end cutting device, and inspecting each said flexible sheet before cutting each said flexible sheet in said first transverse sheet end cutting device.
 10. The method of claim 1 further including providing a plurality of gripper systems and using said gripper systems too convey said flexible sheets. 